Refractory is specific to direct-fired rotary kilns, insulating and protecting the shell of the drum from high internal temperatures. It also functions to maintain heat retention.
Many types of refractory exist, with the most common options being brick or castable. Brick is fired in a furnace under conditions that allow it to achieve better properties than a similar composition castable. Brick is typically used for abrasive material processing, because it is more wear resistant.
Castable refractory comes in a powder form that is mixed with water onsite. The cement-like mixture is then pumped into the rotary kiln lining and is cured for several days.
While castable and brick are comparable in price for similar refractory compositions, the installation cost of brick is higher because it is more labor intensive. In general, the refractory selection is dependent on the kiln temperature, material chemistry, and how abrasive the material is.
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